Basically substituted azaphenothiazines



United States Patent In such formula the benzene can if desired be substituted, for *example, with hydroxy groups halogen, such as Cl, lower alkyl groups, such as methyl, as well as with lower alkoxy groups and the like, X and Y represent oxygen or sulfur, Alk and Alk represent straight or branched chained lower alkylene radicals, R and R are lower substituted or unsubstituted aliphatic radicals, preferably lower alkyl radicals which also can be closed to form a ring, such as a piperidine or pyrrolidine ring. Such ring if desired can be interrupted by a'hetero atom such as in h saaesf. a msr he ine n r a ne nsadica s 31 at E2 ls e slos fl w h Alkz o orm. a n s ch as the piperidine or pyrrolidine ring, The ether-ester compounds according to the invention and their non-toxic acid addition salts possess good pharmaceutical activity, particularly as cough repressing agents. For example, the piperidino-ethoxy-ethyl 'ester of l-azaphenothiazine carboxylic acid when tested on guinea pigs showed an E1). SD of; 15 mg./kg.i.9fuponsubcutaneous injection. Practicallyhs good'acoughfrepressant action was also obtained with the diisopropylaminoethoxy ethyl ester'of l-azaphenothiazine carboxylic acid. Also the diethylamino ethoxy ethyl ester and the diethylaminoethyl thioethyl ester of l-azaphenothiazine carboxylic acids were distinctly active as cough repressants, even though less strong than the first two ether esters mentioned. The above tests were carried out using between 18-24 guinea pigs for each.

In comparison, tests carried out with dimethylaminoisopropyl-l-azaphenothiagine (the only. l-azaphenothiazine derivative which has as yet been placed upon the market) showed that this compound had practically no cough repressant action in non-toxic doses.

Tests carried out with +)-3-methoxyrN-methylrnorphinane-hydrobromide, a commercially. available cough repressant showed an ED. 50 of 25 mg./kg.-.:8.l. The above mentionedpiperidino-ethoXy-ethyl ester compound and the above mentioned 'diisopropylamino-ethyl thioethyl ester compound were respectively 1.7 and 1.4 times as efiicient as the morphinane hydrobromide compound.

The compounds according to the invention can be prepared from a l-azaphenothiazine derivative of the formula s Q n 2,989,529 Patented June 20,, 1961 2 wherein Z represents a halogen or an alkoxy group.

starting compounds can be prepared by reacting 1- a zaphenothiazine with carbonic acid dihalides as described in application S.N. 621,013, filed November 8, 195,6, now U.S. Patent No. 2,934,533, or by reacting a carbonic acid dihalide first with an alkanol to produce a compound of the formula Hal-COOAlk and reacting this compound with l-,az;aphenothiazine.

These compounds are reacted with a compound of the formula I R1 preferably at an elevated temperature it necessary in the presence or an alkaline condensing agent with splitting oil: of hydrohalide or the alcohol corresponding to the alkoxy group.

It is also possible to produce the compounds according to, the invention by reacting the l-azaphenothiazine derivative of the formula so i.

with a compound of the formula H XTAlk ':Y1Alk -=-Z Q PEQQHCQ. em-129 1 .19; at e f rmu p s X Al kr- Y?A ]k 9 than twan u h enra ed with. a mpou d. 1. a fermula HTN/ zinaoi; theform lawith a compound oi the formula z =corax A k Y-A1k z and then reacting. theresulting condensate with a compound of: the formula Example 1 a V 331. r s sf: zea anstmaa ne arb y iws an ride were introduced into parts of 'chlorobenzene and serve to ill ustrate several 20.2 parts of diethylaminoethoxy-ethanol added thereto. The mixture was then boiled for 15 minutes under reflux. After cooling, water was added to the reaction mixture and dilute HCl was added thereto to provide a pH of about -6. The aqueous phase was separated oif, caustic soda solution added thereto and then extracted with ether. The ether extract was washed with water, then dried and the ether distilled off. 17 parts of the diethylaminoethyl ester of l-azaphenothiazine carboxylic acid were obtained. This compound was then dissolved in isopropanol and the solution neutralized with isopropanolic HCl. The monohydrochloride salt which precipitated out after recrystallization had a melting point of 126 to 127 C.

Example 2 8.5 parts of l-azaphenothiazine carboxylic acid chloride and 14 parts of piperidino-ethoxy-ethanol were introduced into 100 parts of chlorobenzene and the mixture boiled under reflux for 5 minutes. After cooling off the precipitated hydrochloride salt of piperidino-ethoxy-ethanol was filtered off on a suction filter. Water was added to the filtrate and the pH thereof adjusted to 5 to 6 with dilute HCl. The aqueous phase was then removed, a caustic soda solution added thereto and then extracted with ether. The ethyl extract was washed with water, then dried with potash and the ether distilled oif. 9.4 parts of the piperidino-ethoxy-ethyl ester of l-azaphenothiazine carboxylic acid were obtained. This product was dissolved in 20 parts of isopropanol and the solution neutralized with isopropanolic I-ICl. The monohydrochloride which precipitated out after recrystallization from isopropanol had a melting point of 160-161 C.

Example 3 26 parts of l-azaphenothiazine carboxylic acid chloride and 37 parts of diethylamino-ethyl-mercaptoethanol were introduced into 300 parts of chlorobenzene and the mixture boiled under reflux for 30 minutes. After cooling, water was added to the reaction mixture and it was washed three times with water. The chlorobenzene phase was adjusted to a pH of 5 with water and dilute HCl. The aqueous phase was separated ofi, alkalized and then extracted with ether. After the ether was distilled ofi an almost quantitative yield of diethylaminoethyl-mercaptoethyl ester of l-azaphenothiazine earboxylic acid remained as a residue. It was dissolved in 50 cc. of water and the solution neutralized with isopropanolic HCl. After the addition of a little acetone and ether the monohydrochlon'de salt crystallized out. After recrystallization from an isopropanol-acetoneether mixture the monohydrochloride salt melted at 118-121 C.

Example 4 When the procedure of Example 3 was repeated, except that diisopropylaminoethyl-mercaptoethanol was used instead of the diethylaminoethyl-mercaptoethanol, the diisopropylaminoethyl-mercaptoethyl ester of l-azaphenothiazine earboxylic acid was obtained, the monohydrochloride of which melted at 104-108 C.

Example 5 26 parts of l-azaphenothiazine carboxylic acid chloride were dissolved in 300 parts of chlorobenzene and 44.2 parts of diisopropylaminoethyl-mereaptoethyl-mercaptan added to such solution. The mixture was boiled under reflux for 30 minutes. After cooling ofi, water was added to the reaction mixture and it was washed three times with water. The organic phase was separated oil and adjusted to a pH of 4 with water and dilute HCl. The aqueous phase was then separated off from the organic phase, alkalized and then extracted with ether. After the ether was distilled off from the extract a 78% yield of the diisopropylaminoethyl-mereaptoethyl-thioester of l-azaphenothiazine carboxylic acid remained as a residue.

It was dissolved in 50 cc. of isopropanol and the solution 4 adjusted to a pH of 4-5 with isopropanolic HCl. Upon addition of a little acetone and ether the corresponding monohydrochloride precipitated out. This salt had a melting point of 144-146 C.

Example 6 12.9 parts of l-azaphenothiazine carboxylic acid methyl ester (M.P. 133-135" C.) were heated in 300 parts of xylene with 7.5 g. B-chloro-fi'-hydroxy-diethyl ether (B.P. 180-185" C.) and 0.2 g. of sodium to boiling for 3 hours. During such boiling the methyl alcohol formed together with about 150 cc. of xylene distilled off. Thereafter 6 parts of diisopropylarnine and 16.5 parts of powdered potash were added and the mixture boiled for 6 hours under reflux while stirring. After cooling, the salt mixture was filtered off and the filtrate extracted with aqueous HCl. The aqueous extract was alkalized and extracted with ether. The ether extract was dried with potash and then evaporated to dryness.

10.8 par-ts of crude diisopropylaminoethoxy ethyl ester of l-azaphenothiazine carboxylic acid were obtained. The crude product was dissolved in isopropanol and the solution neutralized with isopropanolic HCl. The monohydrochloride which is thus obtained melts at 126-129" C.

after recrystallization from isopropanol.

I claim: 1. A compound selected from the group consisting of I free bases of the formula I A (Md do wherein X and Z are selected from the group consisting of oxygen and sulfur atoms and Y is a radical selected from the group consisting of l-piperidino and l-pyrrolidino, R and R are lower alkyl and the non-toxic inorganic acid addition salts thereof.

2. A compound of the formula 3. A compound of the formula 4. A compound of the formula s CzHi 5 6 5. A compound of the formula v i I References Cited in the file of this patent UNITED STATES PATENTS s 2,778,824 Von Seemann Ian. 22, 1957 I 6 2,789,978 Rath Apr. 23, 1957 FOREIGN PATENTS f 515,180 Canada Aug. 2', 1955 Z 7 OTHER REFERENCES Schlichtegroll: Arzn. Forsch., vol. 7, pp. 237-52 cm. (April 1957 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF FREE BASES OF THE FORMULA 